An analysis the following two input-output relationships as basic functions was carried out for the machining of SKD11 alloy tool steel, which is used in cold molds in the automobile industry, with reference to existing examples of the application of quality engineering in metal cutting. <1> Input M: metal thickness,corresponding to energy consumed by machining; output y: electrical energy consumed by the drill spindle. <2> Input M: same as in <1> above; output y:reduction in work piece weight by drilling, corresponding to energy consumed by machining. Results of experiments run with combinations of optimized conditions and comparative conditions were as follows: (1) in comparison with the comparative conditions, with basic function <1> the optimized conditions had a variance improvement effect of 1:6.28 in signal-to-noise ratio and 1:1.66 in sensitivity;(2) with respect to hole diameter error, which is a product characteristic,there was no obvious difference between the optimized conditions and comparative conditions, but the optimized conditions produced better machining, with less flash.
